Clamp



Dec. 23, '1941.

D. H. FINKLE v CLAMP Filed April 18, 1941 Patented Dec. 23, 1941 UNITED sTATEs PATENT OFFICE CLAIVIP' Donald H. Finkle', Los Angeles, Calif. Application April 18, 1941, Serial No. 389,151

' I-Ciaim. (c1. 8 -5) .two or more eral bolts and stop nuts used in fastening the inspection plates, it is necessary that the bolt holes in the inspection plate, in the skin and the "stop nuts all concentrically align. These "stop nuts" are riveted to the inside of the skin and must be held in concentric alignment with theskin and inspection plate holes while the rivet holes are drilled and the rivets fastened in place.

As 'a stop nut has threads for engaging the bolts holdingthe inspection plates, the diameter of the hole in the stopnut necessarily is smaller than the clearance holes in the inspection plates and the skin. All of ,the present clamps for aligning holes are usable only where the holes to be aligned have the same diameters. By the use of my clamp hereafter described I am able to concentrically align holes of different diameter.

My invention is also'usable where the task is the alignment of similar diameter holes and is successful in holding the skin to the structural members and at the same time concentrically aligning the rivet holes while the remainder of the rivet holes are drilled and the rivet fastened.

It is, therefore, an object of my invention to provide a clamp for concentrically aligning holes.

Another object of my invention is to provide a clamp for concentrically aligning holes of .different diameters.

Another object of my invention is to provide I Fig. 3 is a section substantial line 3-3 of Fig. 1; a Fig. 4-is a similar view to Figure 3, partially in section, with the clamp expanded;

Fig. 5 is a section taken on the line 55 of Fig. 4; g I

Fig. 6 is a section showing a modification;

Fig. '7 as section taken on the line I-I of Fig. 6:

1y taken on the A clamp constructed in accordance with my l invention has a-body member I having a hole 2 therethrough for the reception of the split pin 3. The pin 3 is machined from ordinary steel rod and is provided at one end with a shoulder 4 and at the other end with a shoulder 5. The end 6 of the pin 3 is rounded off to aid insertion of this end through the holes to be aligned. The pin 3 has a slot I made by either milling or grinding, formingextensions I3 and I4.

To retain the pin 3 in the body member I. the'pin 3 is flatted on .one side at 8 and a small red 9 is positioned in the hole I0 in body member I adjacent to the flatted side 8. The rod 9 may be riveted in place.

To spread the two extensions I3 and I4 of the pin'3, I-place a small rod II through a hole I2 in the body member I and into the slot I. As this rod II is larger'in diameter than the slot I, the extensions I3 and I4 are spread so .that the total diameter of the extensions I3 and I4 is the size of the hole '2 and the shoulder 5 extends beyond the hole 2 and material can be clamped between the shoulder 5 and the face I5 of the body member I.

I provide a spring I6 positioned betweenthe shoulder 4 and the end I! of the body member I to exert a tension between the face I5 and the shoulder 5 to firmly clamp any material placed therebetween.

To permit the extensions I3 and I4 to spring back to their normal diameter, I drill a hole 24 of suflicient diameter to allow the rod I I to fit loosely therein in the pin 3 so positioned that when the clamp iscompletely compressed as shown in Fig. 4 the rod II will pass therethrough and the extensions I3 and It will spring together and decrease their combined diameters and allow insertion of the end-'5 in the holes I8 and I9 in the skin and inspection plate 2|, respictzively, and through the hole 22 of the stop nu 3.

The usual stop nut. has a'central hole 22 which has threads and a nbre bushing 25 threaded similarly to threads 35. The holes I8 and I! are clearance size. for the bolts which engage the threads 35. The diameters of the holes I8 and I9 are larger than the hole 22 and to concentrically align these three holes the pin 3 is made of such size that when the extensions I3 and I4 are expanded by the rod II the extensions I 3 and Il are a tight fit in the holes I8 and IS. A neck 36 on the extensions I3 and I4 is made the same length as the hole 22 and has atotal diameter, when expanded, substantially that of the hole '22.

The total diameter of the shoulder 5 is larger than the diameter of the hole 22 when the extensions I3 and I4 are expanded by the rod II.

A modification of my invention is shown in- Fig. 6 and enables me to make a slightly cheaper construction with equal advantages to the one previously described. The flatted side 8, the

rod 9 and the hole I0 may be deleted by enlarging the hole 2 as at 2| in the body member I.

In this last-type of construction the rod II needs only to be slightly larger than the normal hole 2 and the hole I2 may be dispensed with. In this type of construction the spring I6 has one end engaging the rod II and the other end engaging the shoulder 4 or the face 2'! of a cap which is the modification to be described.

To assemble this type of clamp, the spring I6 is placed on the pin 3, the rod I I is placed through the hole 24 .and the pin forced through the hole 2,

' Once this type of clamp is assembled, it willnot come apart because the shoulder 5 when the extensions I3 and I4 are expanded is larger than the hole 2 through the face of the body member .I and the spring I6 will force the rod II against the inner side of the body member I at all times and will cause the rod II to slide -into the milled slot I and expand the extensions I3 and Il. Only when the spring I6 is completely compressed, as shown in Fig. 6, will the rod II lie in the hole 24 and permit the shoulder 5 to be inserted in the holes to be aligned.

It will be noted that when the clamp of my invention is to be used to align ordinary rivet holes between two sheets of material, the size of the holes to be aligned will be that of the neck 36 when expanded and when a stop nut" is not to be aligned the full sized portions of the extensions I3 and I I will not extend beyond the face I5.

The modification shown in Fig. 6 is particularly adapted for the ordinary riveting of skin to structural members as the neck 36 extends well into the body member I at all times. This is the preferred type on ordinary rivet work as the shoulder 32, occasioned by the neck 36, sometimes interferes in the insertion of the clamp into comparatively long holes.

In Fig. 6 I have shown a cap rather than a simple shoulder. This cap comprises a simple bushing 28 held to the end of pin 3 by a pin 29 passing through holes in both bushing 28 and pin 3. The face 21 of the bushing takes the place of the shoulder i.

While I have described the preferred embodiments of my invention, I am not limited to the specific forms described therein except as set forth in the appended claim.

I claim:

In a clamp of the class described, a body member, a pin extending from said body member formed with a slot extending longitudinally from one end thereof, a projection upon the slotted end of said pin, said projection being insertable through the holes to be aligned, means for expanding said pin whereby said projection will engage one side of the sheets to be clamped, tension means whereby said sheets are clamped between said bodymember and said projection, and a neck and a shoulder on said pin whereby said pin aligns holes of different diameters.

DONALD H. FINKLE. 

